ok
So hes like a special type of alpha called 'ghost/phantom' theyre so rare that its basically a myth rn. He has the ability to change the second gender of people through knotting and you can probably guess where this is going, the first time he does this unintentionally so he panics and they dont talk to eo properly for a few days.
And after that when they sleep with eo again he does it again and again but this time intentionally.
FURTHER MAJORMAJOR SPOILERS
so basically his friend inwoo finds out and he tells him that he needs to tell yeehyeon that youre slowly changing him into an omega, he asks for some time and his mthrfcking gland plan is that he helps yeehyeon send his brother and girlfriend abroad to escape the uncle and establish an overseas branch of phantom and move there with yeehyeon. And when hes isolated in a place which is new to him and where he knows no one, he'll tell him then so he has no choice but to forgive him and take him back but obvi he finds out before that through shushu. Atp yeehyeon is 50% omega and 50% beta so he tells the ml that he made him feel like a monster and leaves him and accepts an offer to paint overseas along with Yuni.
Thats far how I've read.

Okay novel readers, it’s your time to shine spoiler pls